wip: debug FrameSession nil panic

.github/workflows/e2e.yml

@@ -16,7 +16,8 @@ jobs:
     strategy:
       matrix:
         go: [stable, tip]
-        platform: [ubuntu-latest, windows-latest, macos-latest]
+        # platform: [ubuntu-latest, windows-latest, macos-latest]
+        platform: [windows-latest]
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
@@ -64,10 +65,11 @@ jobs:
       - name: Run E2E tests
         run: |
           set -x
-          export XK6_HEADLESS=true
-          for f in examples/*.js; do
-            ./k6ext run "$f"
-          done
+          export XK6_HEADLESS=true XK6_BROWSER_LOG=trace
+          ./k6ext run -q examples/browser_on.js
+          # for f in examples/*.js; do
+          #   ./k6ext run "$f"
+          # done
       - name: Check screenshot
         # TODO: Do something more sophisticated?
         run: test -s screenshot.png

common/frame_session.go

@@ -304,9 +304,6 @@ func (fs *FrameSession) initFrameTree() error {
 		return fmt.Errorf("unable to get page frame tree: %w", err)
 	}
 
-	// FIXME: frameTree is sometimes nil on Windows
-	// https://github.com/grafana/xk6-browser/runs/4036384507
-
 	if fs.isMainFrame() {
 		fs.handleFrameTree(frameTree)
 		fs.initRendererEvents()
@@ -478,8 +475,15 @@ func (fs *FrameSession) isMainFrame() bool {
 
 func (fs *FrameSession) handleFrameTree(frameTree *cdppage.FrameTree) {
 	fs.logger.Debugf("FrameSession:handleFrameTree",
-		"sid:%v tid:%v", fs.session.ID(), fs.targetID)
+		"sid:%v tid:%v ft:%v", fs.session.ID(), fs.targetID, frameTree)
+
+	if frameTree == nil {
+		// Sometimes on very quick scripts we might not have time to initialize
+		// and frameTree will be nil.
+		return
+	}
 
+	fmt.Printf(">>> fs.ctx.Err: %#+v, frameTree: %#+v\n", fs.ctx.Err(), frameTree)
 	if frameTree.Frame.ParentID != "" {
 		fs.onFrameAttached(frameTree.Frame.ID, frameTree.Frame.ParentID)
 	}